Gary Speed has virtually brought down the curtain on his glittering 21-year playing career - by revealing he is in training for the London Marathon.

Speed, 40, has not played for Sheffield United since suffering a career-threatening back injury last November and has since been given coaching duties alongside manager Kevin Blackwell.

But the former Leeds, Everton, Newcastle, Bolton and Wales midfielder confirmed: "The only training I am doing now is for the London Marathon next April. I am doing it for charity - the Bobby Robson Foundation - and it was all my idea.

"Preparations are going well. I am up to running 10 miles at the moment, and my aim is to complete the full 26-mile course in under three-and-a-half hours.

"I just thought that, with not doing any football training, I should do something else to keep myself in shape. The last thing I want to do is start piling on the pounds if I stop playing.

"Am I hanging up my boots? Put it this way - I have not played for a year and I am 40, so what do you think?

"My back is fine but, to be perfectly honest, I am not missing playing at the moment.

"I am enjoying the coaching side very much, so I am not sure I am too bothered about playing again."

Speed, who became the first player to clock up 500 Premier League appearances and won 85 caps for his country, joined the Blades from Bolton for £250,000 in January, 2008.